totally agree with this from Henry Note how they took 2- 3 degrees out of J early on , factory memo no recurve happened . was 15 at degree initial ( yes!! but ? boom!) , that says only 15 17 more was in the weights
There had to be some problems if not on Sunoco 260 while one can argue this, what really matters in timing is the all in number it reaches , no vacuum . Hemi around 28-29 , wedge low 30 ‘s let initial fall where it may — all the hi po curves are ok .( mho ) and close enough, unless NHRA race Curve is out of play anyway where it matters
I have tied the second heavier spring if it has an extended loop so first spring can still work ok . During street racing days Allows more initial to be in sooner without going over , 260 gas . ( J thinking!) To get it in by 2k doing that but do not ever exceed that max number Getting it in fast risks detonation under 2 -2.5 k heavy load ( pulling trailer , heavy car , 3:20 gear, regular gas “ just once” ) in which case you will have to back off initial , which will pull back your correct number too . If you do not , you risk a hole in piston Which says , in 2025 , leave it all alone be sure “all in “ timing is the right number . And that it is working ok, free of gunk . imho splitting hairs with exact curve
Getting all in number wrong is the big error the golden screwdriver makes by messing even a little with initial ,—- and dial back lights . Get a real timing light like old sears so you can see advance work , solid connection to # 1 plug, not “ inductive pickup “ —- first off its not inductive at all its capacitive and can misfire . Been there w snap on fancy light . Problem was the light not car .
Validation of this is “ what is exact curve of electronic upgrade distributor mopar performance sold for years ?” They made no match to any engine at all !!! Just “ B block”or A block
I tried to get that curve , in my days of spitting hairs Factory was/ is “right on “ use it , and extreme accuracy not in the cards as arbitrarily pulling 2.5-3 out of J post shipment shows . That comes out of the full in advance too , where you are 2500-6500 gas, compression etc gets into all this , above assumes reasonable 10:1 or so and best gas today .. if it pings back down 2 -3 , lose a small amount but avoid disaster . 300 is generally not a 1/4 mile car anyway.
On Mar 11, 2025, at 11:51 AM, henry.schleimer@xxxxxxxxxxxxxxx wrote:
I always find it interesting how each engine gets its own curve and how it changes model to model despite very little change to the engine. Poor old engineers must have spent a long time in the dyno room… Yet despite that, the Direct Connection Performance Book says, as a general rule a multi-purpose high performance machine should have full centrifugal advance by 2000 rpm regardless of the engine (including a 413). And Direct Performance would sell you one with that fast curve. Maybe the factory settings are for a worst case like pulling a caravan up a mountain in the wrong gear? I can’t imagine they were concerned about emissions at the time. Anyway, I would aim for the higher of the factory advance figures at the given rpms (unless you tow a caravan - ha). Henry From: 'ALLAN POZDOL' via Chrysler 300 Club International <chrysler-300-club-international@xxxxxxxxxxxxxxxx>
Sent: Tuesday, 11 March 2025 2:46 AM
To: chrysler-300-club-international@xxxxxxxxxxxxxxxx
Subject: {Chrysler 300} Re: 300K distributor curve chart Yes I did find this info online. My question is has anyone seen a logarithmic chart for the curve through the RPM range for the 64K. The factory gives a range at certain RPM increments, but this does not give the ideal data points. Plus with a range, it will show a pretty fat line. Kind of shotgunning. And with only certain datum points, there would not be a representative curve. Just a straight fat line between the RPM markers. Has anyone had their distributor restored and blueprinted, and have a curve chart to share? Or a factory chart? I would like to dial this in, as I assume that the factory had a distinct curve in practice to squeeze 360 HP out of a single carb 413 for 1964. The service manual only gives a range of degrees at a set RPM.
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